Anchorage assembly for prestressing cables

ABSTRACT

An anchorage assembly for use in the prestressing of a cable which comprises an anchorage member having a bore adapted to receive and retain said cable, and an internal annular recess to co-act with an annular projection formed on a flexible insert provided to seal the annular space between said cable and the periphery of said bore. The flexible insert may be radially split or may be capable of being radially split.

Edwards Sept. 11, 1973 ANCHORAGE ASSEMBLY FOR PRESTRESSING CABLES [76] lnventor: Hugh Jeremy Willis Edwards, 20 Matthew Arnold Close, Cobham, Surrey, England [22] Filed: Oct. 9, 1970 [21] Appl. N0.: 79,495

[30] Foreign Application Priority Data Oct. 16, 1969 Great Britain 50,977/69 [52] U.S. Cl. 24/126, 52/223 L, 285/111 [51] lnt. Cl. Fl6g 111/04 [58] Field of Search 26/126 R, 136 R; 52/223 L; 277/168, 205; 285/111; 16/2 [56} References Cited UNITED STATES PATENTS 1,384,489 7/1921 Shaffer 24/126 C l,686,424 10/1928 Thomson 24/126 C 3,524,228 8/1970 Kelly 24/126 2,774,617 12/1956 Lanninger 285/111 2,975,799 3/1961 Stilwell 285/111 3,205,300 9/1965 Becker.... 24/126 R 3,554,569 1/1971 Gorman.. 277/205 3,573,871 4/1971 Warner 277/168 FOREIGN PATENTS OR APPLICATIONS 516,218 9/1955 Canada 24/136 R 1,390,710 l/1965 France... 285/111 681,164 1/1965 ltaly 285/111 776,948 6/1957 Great Britain 24/126 Primary Examiner-Bernard A. Gelak Att0rneyBaldwin, Wight and Brown [57] ABSTRACT An anchorage assembly for use in the prestressing of a cable which comprises an anchorage member having a bore adapted to receive andretain said cable, and an internal annular recess to co-act with an annular projection formed on a flexible insert provided to seal the annular space between said cable and the periphery of said bore. The flexible insert may be radially split or maybe capable of being radially split.

6 Claims, 8 Drawing Figures PATENTEDSEPI 1 IBM 5757, 390

SHEET 1 OF 2 PATENTEDSEPI 1 ma SHEET 2 er 2 5454 021, WWK

I ment,

ANCHORAGE ASSEMBLY FOR PRESTRESSING CABLES tioned therein, being attached to the shuttering of the structure. Since, when pouring the concrete into the shuttering, there is a tendency for it to flow into one end of the anchorage members, it has been the practice to provide sealing elements to close the spacewhich exists between the stressing cable and the periphery of the bore of each anchorage member. I

It is among the objects of the present invention to avoid, or substantially reduce, the abovementioned disadvantage.

According to the present invention, there is provided an anchorage assembly for use in prestressing a cable, which comprises in combination an anchorage member having a bore adapted at one end to retain the stressing cable therein, anda sealing element of flexible material adapted to be received in the other end of the bore, wherein the said other end of the bore is formed with an annular recess and the sealing element is formed with an external annular rib adapted to engage, and be retained in, the said annular recess.

Theinvention is illustrated by way of example in the accompanying drawings in which,

FIG. 1 is an elevation of one end of an anchorage member: a cable, and sealing element,

'FIG. 2 is a section on the line 2-2 of FIG. 1,

FIG. 3 is an'elevation of the other end of the anchorage member, i

FIG. 4 is an enlarged detail of part of FIG. 2,

FIG. 5 is an end elevation of one form of sealing ele- FIG. 6 is a section on the line 6-6 of FIG. 5, and

FIGS. 7 and 8 are respectively an end elevation and a side elevation of a preferred form of tool.

Referring to' FIGS. 1' to 4 of the drawings, there is shown an anchorage member 1. In use, a pair of these anchorage members are adapted to be temporarily attached to the shuttering at each end of a structure, and

thereafter, to be firmly held in position by the concrete. The anchorage members 1 are each formed with an axial bore 2 through'which one end of a stressingcable is passed, one end 3 of the bore 2 being tapered to receive, in known manner, wedge-shaped gripping elements by which the cable is anchored therein, and the other end 4 of the bore 2 being generally cylindrical.

The said other end 4 of thebore 2 is formed, at a position a short distance from the end face of the member,-with an annular recess 5, the extreme end 6 of the bore being fonned to taper outwardly from the recess 5- to provide a lead-in surface.

A sealing element, as shown in FIGS. '5 and 6, to prevent the ingress of concrete into the bore 2 of the anchorage member is provided, in use, to fill the annular space between the periphery of the bore 2' and the stressing cable. The sealing element comprises an annulus 7 of flexible material, preferably synthetic plaselement in said annular recess.

tics material, having a bore 8 to fit over the cable and being formed on its outer periphery with an annular projection or rib 9 having an inclined leading edge 10. The bore of the annulus is preferably formed to conform to the outer periphery of the cable and the annulus is split, or capable of being split, radially to facilitate positioning thereof over the cable. The annulus 7, in order to increase its flexibility, is formed wth spaced circumferentially disposed recesses l l leaving reinforcing webs 12.

In use, the stressing cable is threaded through the bore 2 of each anchorage member which is attached to the shuttering. The sealing member is then clipped over the cable, hence the object of providing a split annulus, and positioned adjacent the end of the anchorage member 1. In this position, using the tool as shown in FIGS. 7 and 8, the sealing member is forced into the end of the bore. Due to the relative tolerances of the bore and the outer diameter of the sealing member, and due to the compressibility of the plastics material, .the sealing member is compressed sufficiently to be forced over the lead in taper 6 and the buttress step provided by one side of the recess 5 in the anchorage member, whereupon it immediately expands to its natural size so that the projection or rib 9 is tightly engaged in the recess 5. 1

The tool, as can be seen from' the drawings, is preferably in the form of a U-shaped tubular element 13 having a handle 14 secured to the base of the U so that, in use, the U-shaped element 13 is placed in position over the cable and one end surface thereof is used to push the sealing element axially into the bore of the anchorage member. I

Iclaim: a

1. An anchorage assembly for use in prestressing a cable, whichcomprises in combination an anchorage member and a sealing element, said anchorage member having'an axial bore therethrough for receiving said cable, one end of said axial bore having a tapered portion for receiving a wedge device by'which the cable is retained therein, and the other end of said axial bore having a generally cylindrical portion and an annular recess, said sealing element is formed externally with a cylindrical body and an annular radially outwardly directed projection, saidannular recess including'a radially inwardly extending portion at one end of said recess remote from said tapered portion, said sealing element being seated in said axial bore with said annular projection and cylindrical body being respectively seated within said. recess and upon said cylindrical portion, and said radially extendingportion inter'engages with said annular projection for retaining said sealing -2. An assembly as defined in claim 1 wherein theextreme end of said other end of said axial bore includes a tapered lead-in surface adjacent said annular recess for facilitating entry of said sealing element into said anchorage member.

3. An assemblyas defined in claim 2 wherein said sealing element is radially split along its length for facilitating positioning thereof around a stressing cable.

4. An anchorage assembly for use inprestressing a cable, which comprises in combination an anchorage member and a sealing element, said anchorage member having an axial-bore therethrough for receiving said cable, one end of said axial bore having a tapered portion for receiving a wedge device by which the cable is re.-

of spaced radially disposed reinforcing webs.

5. An assembly as defined in claim 4, in which said annulus is radially split to facilitate positioning thereof around a stressing cable.

6. An assembly as defined in claim 5, in which the ex treme end of said other end of said axial bore is tapered to facilitate entry of said sealing element into said annular recess in said anchorage element. 

1. An anchorage assembly for use in prestressing a cable, which comprises in combination an anchorage member and a sealing element, said anchorage member having an axial bore therethrough for receiving said cable, one end of said axial bore having a tapered portion for receiving a wedge device by which the cable is retained therein, and the other end of said axial bore having a generally cylindrical portion and an annular recess, said sealing element is formed externally with a cylindrical body and an annular radially outwardly directed projection, said annular recess including a radially inwardly extending portion at one end of said recess remote from said tapered portion, said sealing element being seated in said axial bore with said annular projection and cylindrical body being respectively seated within said recess and upon said cylindrical portion, and said radially extending portion interengages with said annular projection for retaining said sealing element in said annular recess.
 2. An assembly as defined in claim 1 wherein the extreme end of said other end of said axial bore includes a tapered lead-in surface adjacent said annular recess for facilitating entry of said sealing element into said anchorage member.
 3. An assembly as defined in claim 2 wherein said sealing element is radially split along its length for facilitating positioning thereof around a stressing cable.
 4. An anchorage assembly for use in prestressing a cable, which comprises in combination an anchorage member and a sealing element, said anchorage member having an axial bore therethrough for receiving said cable, one end of said axial bore having a tapered portion for receiving a wedge device by which the cable is retained therein, and the other end of said axial bore having a generally cylindrical portion, wherein said other end of said bore is forMed with an annular recess and said sealing element is formed externally with an annular projection, said annular projection being disposable within said annular recess for retaining said sealing element in said anchorage member, said sealing element comprising an annulus formed on its outer periphery with said annular rib, said annulus being formed with circumferentially spaced recesses presenting a plurality of spaced radially disposed reinforcing webs.
 5. An assembly as defined in claim 4, in which said annulus is radially split to facilitate positioning thereof around a stressing cable.
 6. An assembly as defined in claim 5, in which the extreme end of said other end of said axial bore is tapered to facilitate entry of said sealing element into said annular recess in said anchorage element. 